CT ECO Basic Data Guide

Soil Flooding Class

Example of Soil Flooding Class


Soil susceptibility to flooding is the temporary inundation of an area caused by overflowing streams, by runoff from adjacent slopes, or by tides. Water standing for short periods after rainfall or snowmelt is not considered flooding, and water standing in swamps and marshes is considered ponding, rather than flooding. Frequency classes are expressed as none, very rare, rare, occasional, frequent, and very frequent. Estimates of flooding class are based on the interpretation of soil properties and other evidence gathered during soil survey field work. For additional documentation including a description of the map legend for Soils Flooding Class, refer to the CT ECO Complete Resource Guide for Soils Flooding Class.

All soil information included in the CT ECO maps and map viewers is from the Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS), which is based on information originally published on the set of Soil Survey quarter quadrangle maps that cover Connecticut.


The purpose is to identify those soil map units that may be subject to flooding in comparison to those that may be wet for other reasons such as high water table or ponding. The susceptibility of soils to flooding is an important consideration for building sites, sanitary facilities, cropland, and other uses. Additional information on the soil flooding duration and month of occurrence is available at the Web Soil Survey http://websoilsurvey.nrcs.usda.gov/.

Use Limitations

This data set is not designed for use as a primary regulatory tool in permitting or siting decisions, but may be used as a reference source. This is public information and may be interpreted by organizations, agencies, units of government, or others based on needs; however, they are responsible for the appropriate application. Federal, State, or local regulatory bodies are not to reassign to the Natural Resources Conservation Service any authority for the decisions that they make. The Natural Resources Conservation Service will not perform any evaluations of these maps for purposes related solely to State or local regulatory programs.

Dataset Information

  • Status - This information is updated as needed. The previously published county soil surveys (published between 1962 and 1981) are superseded by this official soil information. County soil surveys are for historical use only.
  • Date of Data - The original data was collected from published surveys from 1962 to 1981, field mapping from 1985 through 2001 and additional attribute documentation to 3/23/2007.
  • Map Scale and Accuracy - 1:12,000 (1 inch = 12,000 feet). Minimum delineation is 3 acres in size.

Additional Documentation

  • Soil Flooding Class - CT ECO Complete Resource Guide
  • Soil map unit GIS Metadata - Contains technical documentation describing the Soil map units data and the data sources, process steps, and standards used to collect, digitize, and store this information in a geographic information system (GIS).
  • Soil interpretation GIS Metadata – Contains technical documentation describing the data table that defines soil interpretation such as Hydric Soils, Inland Wetland Soils, and Potential for Subsurface Disposal Systems. This lookup table is related to the soil map unit data and used to create the various soil interpretations included in CT ECO.


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